Pure fluid amplifier with improved gain characteristics



0 United States Patent [72] Inventor Robert W. Young 3,181,546 5/1965 Boothe 137/8l.5 DetrolLMkhigim 3,261,372 7/1966 Burton 137/81.5 [21] Appl. No. 718,571 3,262,466 7/1966 Adams et al. 137/81.5X [22] Filed Aprll3, 1968 3,272,214 9/1966 Warren 137/815 [45] Patented N v-10,1970 3,277,915 10/1966 Dockery 137/81.5 [73] Assignee The Bendix Corporation 3,282,280 11/1966 Horton..... 137/81.5 Incorporation of Delaware 3,331,379 7/1967 Bowles 137/815 3,366,131 1/1968 Swartz 137/815 54 PURE FLUID AMPLIFIER WITH IMPROVED GAIN Prmwry Exammersam}lel scott I CHARACTERISTICS Attorneys-1ames L. O Brien and Plante. Hartz, Smith and 8 Claims, 3 Drawing Figs. P

[52] U.S.Cl 137/815 [51] Int. Cl F150 l/08 ABSTRACT: A pure fluid amplifier which includes a pressure [50] Field of Search 137/815 equalizing passage that communicates with opposite sides f the deflectable jet in the amplifier so as to reduce the pressure [56] References cued differential across the jet thereby enabling deflection of the jet UNITED STATES PATENTS by means of a control fluid stream at a lower pressure and 3,016,063 1/1962 Hausmann 137/815 flow.

Patented; N v; 10, 1970 3,538,932

:T'IG. 3

INVENTOR ROBERT w. YOUNG ATTORN EY PURE FLUID AMPLIFIER WITH. IMPROVED GAIN CHARACTERISTICS BACKGROUND OF THE INVENTION The term pure fluidamplifier refersto a-system in which amplification of one or more of the parameters of a flowing fluid jet can be effected in apparatus involving no moving parts. Fluid at supply pressure is delivered. to a power nozzle which issues a stream of fluid toward the apex-of a divider located downstream from the nozzle. Diverging attachment walls, inthe case; of a bistable amplifier, are disposed on opposite sides of thedivider and the jet from the power noule will initially attach to one .of the; walls. Control nozzles are disposed on opposite sides of the fluid jet at positions adjacent the power nozzletl Uponthe issuance, of a fluid stream from one of the control nozzles, thefluid jet is deflected from the one wallcausing the jet toattach to the other one of the walls and flow to a first receiving portlocated toone side of the di- With reference to thedrawing, the fluid amplifier of this invention, indicated generally at 10, is illustrated in FIGS. l-S, inclusive, as including a laminated body 12. In the illustrated embodiment of the invention, the body 12 consists of five laminae, namely, cover laminae 14 and 15, a jet lamina 16, a divider lamina 18, and a passage forming lamina 24]. The lamina 14 is provided with an inlet 22 for supply fluid, at pressure P,, and inlets 24 and 26 for control fluid, at pressures P and P respectively.

The jet lamina 16 is formed with a passage configuration providing for a power nozzle 24 located between and confined by the laminae 14 and 18, and a pair of diverging attachment walls 26 and 28 having inlet ends 30'and 32 disposed adjacent the power nozzle 24. The lamina 16 also provides for the formation of control nozzles 34 and 36 which are disposed on transversely opposite sides of the power'nozzle 24 at positions I between the power nozzle 24 and the attachment wall ends 30 vider and at-the end of the wall to which the jet is attached.

Upon the issuance of a fluid stream from the other control nozzle, the fluid jet is deflected back to its initial position attached to theone wall causing the fluid in the jet to flow. to a second receiving-port located on the other side of the divider and at the cadet thefirst attachment wall. The gain of the amplifier, namely, the ratio of the fluid pressure at the receiving port to the fiuid'pressure in-the control stream which deflected the jet to cause-it to supplyv pressure to the receiving portis necessarily limited by. an-attachment bubble which exists on the attachment wall'at the end thereof closest to thepower nozzle. This attachment bubble is a negative pressure zone which" holds the jet against the attachment wall and prevents.

ready detachment of the jetfrom the. wall. In wall attachment type fluid amplifiers, the existenceof this bubble area has limited theavailable gain.

SUMMARY. OF THE'INVENTION bodiment of the invention, the opposite end of the passage. communicates .with the opposite-side of the jet. This passage thus communicatesthe negative pressure zone in the bubble with a high pressure zone. As a result, the pressures in these high and lowpressure zones tend to equalize, so as to reduce the pressure differentialacross the jet and thereby make it easier to detach the'jet from its attachment wall. In a bistable amplifien the ends of the-,passage are disposed adjacent the two attachment wallsso that :irrespective'of which wall the jet is attached to, the passagecan reduce the pressure differential across the; jet. As a result, a control stream of fluid at a reduced pressure is effective to deflect the I jet from one wall to' the other'therebyproviding the. amplifier with improved. gain characteristics, Thus for a given design, much higher pressure;

flow and power gains are obtainable, faster switching timesare obtainable. and. the amplifier is provided with an increased fanout capability;

It is an object ofthe present invention, therefore, to provide an improved pure.fluid-amplifier.;

7 Further objects,.features and advantagesof this inventionv will become apparent-frame consideration ofthe following description; the appendedclaims,. and the accompanying drawinginwhich:

FIGS. l'and,2. are sectional views of thepure fluid amplifier of this invention, as seen from the lines 1-1 and 2-2 in FIG. 3, with the cr'oss hatching removed for the purpose of clarity; and

F IG. 3 is anxenlargedfragmentary transverse sec'tionalview of the fluid amplifier of this invention.

and 32. The lamina 16 also provides for the formation of a divider 38 between-the attachment walls 26 and 28 which com-' municate at their outlet ends 40 and 42, respectively, with receiving ports 44 and 46, respectively, formed in the lamina 14.

The confining lamina 18 is formed with a pair of openings 48 and 50' which communicate with the attachment walls 26 and 28, respectively and also communicate with the ends of a passage 52 formed in the lamina 20 for a purpose to appear presently.

In the operation of thepure fluid amplifier 10, assume that supply fluid at a pressure P, is supplied to inlet 22 so that it-will issue from power nozzle 24 as a fluid jet. Assume further that a supply of control fluid to inlet 26 has issued from control nozzle 36 as a stream of fluid at. pressure P and has impinged on the jet from nozzle 24 causing the jet to be deflected onto the attachment wall 26. Once the jet has attached itself to wall 26, it will, inthe absence of any other forces on the jet, continue to flow along the wall 26 and into the receiving port 44.

During such flow, the jet creates a bubble zone, indicated generally at .54 a in FIG. 2 on the wall 26 located generally between the wall inlet end 30 and the divider 38. This bubble zone 54 is a negative pressure area. In other words, a vacuum exists in the bubble zone 54and this vacuum tends to hold the jet against the wall 26. For this reason, in this area ofthe amplifier 10, a minus sign is used in the drawing to indicate the vacuum condition. On the opposite side of the attached jet, a corresponding high pressure area exists and this area is indicated in the drawing by a plus sign This pressuredifferential across the jet tends to hold the jet on the wall to which it is attached, but it also makes it more difficult to deflect the jet off the wall 26. In other words, a fluid control stream atan increased pressure is required at nozzle 34m deflect the jet in conventional fluid amplifiers of this type.

In the fluid. amplifier 10, the passage 52 communicates at the openings 48 and 50 with the negative and positive pressure zones, respectively so that the pressures in these zones will tend to equalize, without actually becoming equal. As a result, the pressure differential across the jet is decreased and a stream of control fluid at a reduced pressure from nozzle 34 will be effective to flop the jet from an attached position'on the wall 26 to an attached position on the wall 28, in the illustratedbistable form of fluid amplifier. When the jet has attached to the wall 28, the opening '50 at one end of the passage 52 will communicatewith the negative pressure bubble zone created'by the attached'jet and the opening 48' at the opposite end of the passage 52 will communicate with a high pressure area. As a result, the passage 52 will function, when the jet is attached tothe wall 28, exactly as described above in the case of attachment of the jet to the wall 26, except that the direction of pressure equalizing flow in the passage 52 will be reversed.

It is to be understood that it is also within the scope of this invention to connect a passage tothe-bubble zone 54 and the ambient atmosphere or some other reference pressure zone a a pressure abovethebubble pressure, since this arrangemen is effective to reduce the pressure differential across the jet In all instances, the output pressure of the amplifier at an outlet port 44 or 46, relative to the control pressure, at either the nozzle 34 or the nozzle 36, required to deflect the jet is increased so that the gain characteristics of the amplifier 10 are improved.

It will be understood that the pure fluid amplifier with improved gain characteristics which is herein disclosed and described is presented for purposes of explanation and illustration and is not intended to indicate limits of the invention, the scope of which is defined by the following claims.

I claim:

1. In a pure fluid amplifier which includes a body formed with an attachment wall having an end, power nozzle means located adjacent said wall and capable of supplying a fluid jet that can attach to said wall creating a low pressure zone between said jet and said wall adjacent said wall end, and nozzle means adjacent said wall end for directing a stream of control fluid against a side of said jet which is attached to said wall as to tend to deflect said jet in a direction away from said wall; the improvement comprising passage means in said body having an end disposed adjacent said side of said jet and adjacent said wall end in communication with said low pressure zone and also including means for supplying fluid under pressure to said low pressure zone via said passage sufficient to increase the pressure in said zone while maintaining said zone at a pressure below that in the area on the opposite side of said jet, whereby said passage provides for a reduction in the pressure differential across said jet so that a stream of said control fluid and reduced pressure is capable of deflecting said jet.

2. In a fluid amplifier having the structure set forth in claim 1, wherein said means for supplying fluid includes a second end of said passage means communicating with the zone in said body on the opposite side of said jet. wall.

3. In a fluid amplifier having the structure set forth in claim 2, wherein said amplifier includes a second attachment wall disposed in a space diverging relation with said first mentioned attachment wall and wherein said second of said passage means ends is disposed adjacent said second attachment wall.

4. ln a fluid amplifier having the structure set forth in claim 1; wherein said body is of a laminated construction and said fluid jet is confined between a pair of laterally spaced laminae in said body and said passage means extends through a lamina in said body spaced laterally from said pair of laminae.

5. ln a fluid amplifier having the structure set forth in claim 4, wherein said body also includes a divider disposed downstream from said power nozzle means and spaced from said attachment wall, and wherein said passage means extends generally transversely of the direction of flow of said fluid jet at a position between said power nozzle means and said divider.

6. In a fluid amplifier having the structure set forth in claim 1, wherein said amplifier includes a second attachment wall disposed in a spaced diverging relation with said first mentioned attachment wall having a second wall end adjacent said power nozzle means, said power nozzle means being further capable of supplying a fluid jet that can attach to said second wall and create a low pressure zone between said jet and said second wall adjacent said second wall end, and second nozzle means adjacent said second wall end for directing a stream of control fluid against a side of said jet which is attached to said second wall so as to tend to deflect said jet in a direction away from said second wall; the further improvement comprising second passage means in said body having a pair of ends, one of said second passage means ends being disposed adjacent said side of said jet and adjacent said second wall end in communication with said low pressure zone and the other of said pair of ends communicating with a zone wherein the pressure is higher than the pressure in said low pressure zone, whereby said second passage provides for a reduction in the pressure differential across said jet so that a stream of control fluid from said second nozzle means at a reduced pressure is capable of deflecting said jet.

7. In a fluid amplifier having the structure set forth in claim 6, wherein said body also includes a divider dis osed downstream from said power nozzle means and space from said attachment walls, and wherein said passage means one ends are disposed between said power nozzle means and said divider.

8. In a fluid amplifier having a structure set forth in claim 6, wherein said passage means other ends communicate each with the other. 

